The title of this work, Of Mice and Men, comes from a poem by Scottish poet Robert Burns. The poem is called "To a Mouse" or the longer title "To a Mouse, on Turning Her Up in Her Nest, with the Plough." The long title is self-explanatory. The speaker discusses how he destroys a mouse's nest with a plough. The mouse has constructed the nest to survive during the winter. The mouse is left out in the cold. The mouse had hoped to live comfortably through the winter. The speaker of the poem sympathizes and says:
The best laid schemes of mice and men
Go often askew,
And leave us nothing but grief and pain,
For promised joy!
The mouse put his hopes in the nest. Curley's wife and Lennie also have dreams and these dreams/schemes do go "askew." Curley's wife laments the fact that she never became an actress. She tells Lennie:
Coulda been in the movies, an’ had nice clothes—all them nice clothes like they wear. An’ I coulda sat in them big hotels, an’ had pitchers took of me.
She had dreams but she married Curley instead, leaving her with a lonely life on a ranch. She constantly seeks out companionship (even with Lennie) because she is so lonely. Her dreams ("promised joy") of becoming an actress will have to remain dreams. Lennie has dreams of owning a farm with George. His plans for the farm also "go askew." Both Curley's wife and Lennie have dreams and they both end up being disappointed. Their "promised joy" always eludes them.
Other than Curley, who Curley's wife claims to dislike, she has no friends on the ranch. She doesn't really fit in. Lennie doesn't fit in anywhere. Her death is accidental and Lennie's is not, but they both die dreaming of better lives.